Auto makers and the National Highway Traffic Safety Admin. will iron out details in the coming months regarding ways to reduce distracted driving amid a rush of new technology coming to market, including how seriously the regulator’s final guidelines should be taken.

“It’s a very large effort and it will dramatically change what people can do in a moving vehicle,” says Paul Green, a research professor at the University of Michigan who has studied the phenomenon for three decades.

Distracted driving arguably represents the most complex safety issue ever to face the industry, because unlike an enhancement such as stability control it must take into account human behavior that differs from person to person. Consumers also want the latest mobile technology with them on the go, and any auto maker failing to meet those demands stands to lose.

Meanwhile, regulators must wrestle with some of their most common notions surrounding vehicle safety, such as the level of protection for which they should strive and how much evidence is necessary to prove a new technology is unsafe for use in a vehicle.

The good news is auto makers already are following a set of industry-made guidelines first conceived more than a decade ago and continually updated.

“The industry started looking at this issue long before the general public became interested, and the guidelines are a living document,” says Wade Newton, a spokesman for the Alliance of Automobile Manufacturers, which represents the industry in Washington.

Nonetheless, the NHTSA guidelines will be a topic of hot debate within the industry until made final by the end of the year.

The regulator released a first draft of its 177-page guidelines earlier this year and three public hearings have been held in Washington, Chicago and Los Angles to gather industry testimony.

The opportunity to submit written comments wrapped up in June and NHTSA signaled the guidelines would enter a final phase by releasing a blueprint to ending distracted driving a week ago.

Several key industry concerns have emerged, according to a WardsAuto analysis of auto maker comments on the proposed NHTSA guidelines. Among the top-line items are concerns over how much authority the voluntary guidelines will carry.

Green says protecting people from their own behaviors, such as sending a text message from behind the wheel or entering a destination into a navigation system while the vehicle is in motion, makes it difficult for NHTSA to declare absolute design rules for auto makers to follow. The amount of distracted-driving research to back a rule remains relatively small.

“A rule would be difficult,” Green tells WardsAuto in an interview.

Honda is asking NHTSA to bind the guidelines with a memorandum of understanding, as the regulator has done on other voluntary standards such as those asking auto makers to design cars with compatible bumper heights.

The industry and NHTSA also appear at odds over adding lockouts, or the ability to limit or disable at certain times technologies demanding both visual and manual attention from the driver.

For example, NHTSA’s preliminary guidelines suggest locking out dynamic-navigation maps while the vehicle is in motion. But as Volvo points out in its comments to the regulator, it has found real-time maps reduce the driver’s workload because he can plan for route changes. This enhances the driver’s decision-making and comfort level.

“This will consequently lead to more attentive and balanced driving,” the auto maker says in its comments.

Volvo also objects to locking out record-album art from audio-system display screens, questioning NHTSA’s logic behind the proposal. “Visual images are often intuitive and require only a momentary glance in order to be recognized and identified,” the auto maker says.

General Motors worries blanket lockouts will lead to greater use of portable devices inside cars, such as smartphones and aftermarket navigation systems.

“Guidelines for interactions with non-integrated (hand-held or portable) devices are urgently needed,” the auto maker says, asking NHTSA to also recognize in its final instructions the useful role voice-based interactions can play in assisting the driver.

NHTSA plans to address portable devices in later guidelines, but comments from auto makers analyzed by WardsAuto urge the regulator to include them in the first round.

Many auto maker comments on portable devices suggest they be made compatible with the vehicle’s electronics. That way, drivers can plug them in and operate them through the vehicle system, although that could prove challenging given the vastly shorter development times followed by portable device makers.

Auto makers also want NHTSA’s research on driver interaction with in-vehicle electronics to be performance-based instead of designed based. In other words, the regulator should test how well a particular system works rather than whether it meets specific design criteria.

“It boils down to how long it takes to perform a task,” says Green, who advises NHTSA to include estimates in its final guidelines. Otherwise, auto makers will waste money testing hardware that never should have lived beyond a sketch.

Green also recommends the development of workload managers inside vehicles, because driving environments change quickly and the technology exists to determine in real time how much attention must be devoted to the roadway.

Nissan takes issue with NHTSA carrying over from the Japan Automobile Manufacturers Assn. guidelines the “30-character-limit” for displaying information. The auto maker helped develop the character limit in the 1990s and warns it takes many fewer Japanese characters to express an idea than it does in English.

Nissan believes it is not appropriate to carry over from the JAMA guidelines the 30-character limit to an English-based guideline,” the auto maker says.

Volkswagen suggests NHTSA scrap the notion of guidelines for in-vehicle electronics, saying the current Auto Alliance standards adhered to by the industry is sufficient. The auto maker points out NHTSA’s own research shows technology such as navigation and enhanced infotainment systems accounts for only 0.5% of crashes.

Volkswagen believes that NHTSA’s efforts to impose new distraction guidelines for in-vehicle telematics systems will not only fail to improve motor vehicle safety but can be expected to make it worse.”

However, Green believes NHTSA guidelines will make a difference. “Over time, we will get there,” he says.

jamend@wardsauto.com